If the Ki-84 is brought to AH, as it SHOULD be, then HiTech should model it the way it actually performed FOR THE JAPANESE DURING THE WAR, with 100 octane fuel, not the 150 octane that became available AFTER Japan capitulated. The Frank was in WarBirds and I believe it was modelled that way, but I don't know for sure.
If we want HiTech to model all the might-have-beens then AH will lose all realism. If we're going to go down that path, then let's bring in the Bearcat, XF6F-6, F-80, Sea Fury, Tigercat, and a host of others that almost made it into combat.
Friendly regards, Shuckins